From mboxrd@z Thu Jan  1 00:00:00 1970
Message-ID: <008701c16c9c$57155b80$2248dec2@falken>
From: "Chris Hollis-Locke" <chris@cjl1.demon.co.uk>
To: <9fans@cse.psu.edu>
References: <20011113230455.25131199B9@mail.cse.psu.edu>
Subject: Re: [9fans] dhog the corruptor!
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Date: Tue, 13 Nov 2001 23:38:46 +0000
Topicbox-Message-UUID: 21d4bb76-eaca-11e9-9e20-41e7f4b1d025

> Brucee's implementation just patches the call to point to the
> correct destination.  You don't have to walk any machine code.

MS VXDs work in a similar way - they call it something like
'snap' linkage.  The 'unlinked' call is to a lookup function that
patches the caller (determined by return addr on the stack) to
the actual entry point.  The downside is that you cannot easily
unload or replace a driver that is linked in such a way, which
explains why there are so many "You must now reboot your computer"
messages.
The new WDM may do things differently, I haven't looked at that yet.